Dairy starter culture delivery system and method thereof

Abstract

A delivery system for introduction of a starter culture directly into a dairy process line, comprising a sealed enclosure having outlet means for connecting the enclosure to the process line, the sealed enclosure containing the starter culture and / or milk clotting enzyme. The system can be used to introduce a dairy starter culture directly into a closed dairy process line without risk of contamination.

Description

The present invention relates to the field of manufacturing dairy products by the use of starter cultures and it provides a safe and convenient system for delivery of such starter cultures directly into the dairy process line.TECHNICAL BACKGROUND AND PRIOR ARTMicroorganisms are involved in the manufacture of most dairy products. Bacterial cultures, in particular bacteria which are generally classified as lactic acid bacteria are essential in the making of all fermented milk products, cheese and butter. Cultures of such harmless bacteria are called dairy starters and they impart specific features to various dairy products by performing a number of functions.Thus, as an example, the starter cultures ferment lactose to lactic acid, and since the coagulation time by milk clotting enzymes is decreased by the increase in milk acidity, starter cultures aid the enzymatic coagulation of milk in cheese making.A further example is that the rapid lactic acid development throughout the productio...

AI Technical Summary

Benefits of technology

It has now been found that it is possible to add the starter culture and the milk clotting enzyme preparation simultaneously to the cheese milk and obtain a satisfactory cheese manufacturing process including a yield of cheese which is comparable with that obtained with the conventional process. It was also found that cheese starter cultures can retain viability and metabolic activity in an aqueous phase containing a milk clotting enzyme. These unexpected findings has made it possible to provide a method according to the invention wherein the starter culture concentrate is provided in the sealed enclosure in combination with a milk clotting enzyme as mentioned above.

It is an advantageous feature of the method according to the invention that a suspension / solution of the starter culture and / or the milk clotting enzyme which is prepared according to the present invention is stable with respect to viability and metabolic activity for an extended period of time, such as up to and including 24 hours or longer such as up to and including 48 hours or even up to and including 72 hours or longer. Evidently, this feature implies that the method is very flexible in that several starter culture suspensions for use over 1-3 or more days can be prepared simultaneously and used when needed.

In preferred embodiments the enclosure is designed as a bag having an opening for loading with starter culture, which is delimited by sealable parts, and means permitting the enclosure to be suspended. Furthermore, the sealed enclosure can be provided with threaded outlet means to permit screw connection of the enclosure to the process line or any other connection providing a substantially aseptical introduction of the starter culture suspension into the process line. The screw connection can be further protected against any damages under transportation with a screw cap which is removed prior to the connection of the enclosure to the process line. In a specific embodiment, the outlet means of the enclosure comprises one or more layers of a metal foil, such as an aluminium foil, to prevent introduction of atmospheric air into the sealed enclosure. Furthermore, the enclosure may comprise a clip or any other means for separating the starter culture concentrate in the enclosure from the outlet means.

It is thus a significant feature of the delivery system according to the invention that it provides the possibility to supply "customized" or tailor-made packagings of starter culture and / or milk clotting enzyme, not only with respect to amounts of active components but also in respect of the selection of starter culture strains and composition of multi-strain starter cultures.

From the above description of the use of the delivery system in the method according to the invention it is evident that a major advantage associated with the delivery system is the fact that it makes it possible to inoculate the milk in a closed dairy process line with the starter culture without opening the closed system to the environment.

Problems solved by technology

A further example is that the rapid lactic acid development throughout the production process caused by the starter cultures restricts the growth of contaminating micro-organisms.

However, these currently used methods of applying dairy starters involve several problems in modern dairy plants where process lines including reservoirs, vessels, containers, vats, centrifuges, heat treatment equipment, filling equipment and pipelines connecting the elements of the process line are essentially completely closed systems.

Any process step which involves that the closed system be opened to the environment evidently involves a serious risk of contaminating the process line with undesired organisms such as milk spoilage bacteria, e.g. Bacillus species or gram negative bacteria or bacteriophages which attack the starter culture organisms resulting in fermentation failures.

In addition to the risk of contaminating the process line, use of bulk starters propagated at the dairy involves the following problems: (i) the preparation of the bulk starter is very labour intensive and it occupies much space and equipment, (ii) there is a considerable risk of contamination with spoilage bacteria and / or phages during the step of propagation and (iii) by passing a mixed population of starter bacteria from one bulk starter to the next, a selection of strains will occur over time whereby the initial desired characteristics of the culture may deteriorate.

Similar to the use of bulk starters, the use of DVS-starter cultures also involves a risk of contamination and implies a high degree of manual handling.

It is therefore evident that the above problems associated with the current use of starter cultures have become more prominent and enlarged.

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